He took aim at Sheriff Benny Napoleon, who is also expected to soon announce his bid for mayor, saying that the Wayne County Sheriff has no financial experience.

Duggan, touting his own financial turnaround experience at the Detroit Medical Center, said the governor would never back away from the prospect of appointing an emergency manager in Detroit "if we elect a mayor in this city who needs financial training wheels."

Napoleon was active on Twitter during the speech, appearing to respond to Duggan in a few posts:

Duggan reiterated his opposition to the governor potentially appointing an emergency manager, saying state takeovers in Benton Harbor and Ecorse have lasted years without dramatic results.

Former Police Chief Warren Evans came out in support of Duggan, a former Wayne County Prosecutor, during the campaign launch, giving a possible clue as to who might be considered to lead public safety if he is elected.

Duggan also touched on Belle Isle, making it clear he would push for entry fees on the island park.

"If the community had faced reality and agreed to the fee in 1998, that island would look dramatically different today," Duggan said.